
Since \(q^d, \dot{q}^d, \ddot{q}^d \in \mathcal {L}_{\infty }\) , it can be verified using (REF )-(REF ) that \(\exists \theta _i^{*} \in \mathbb {R}^{+}\)  \(i=0,1,2\)  such that the upper bound of \(\sigma \)  holds the following LIP structure [1]}:
\(||\sigma ||\le \theta _0^{*}+\theta _1^{*}||\xi ||+ \theta _2^{*}||\xi ||^2 \triangleq Y(\xi )^T \Theta ^{*},  \) 
